Effect of Chlorogenic Acid Administration on Glycemic Control,Insulin Secretion,and Insulin Sensitivity in Patients with Impaired Glucose Tolerance

Abstract

Chlorogenic acid has been described as a novel polyphenol with metabolic effects on glucose homeostasis. The aim of this study was to evaluate the effect of chlorogenic acid administration on glycemic control, insulin secretion, and insulin sensitivity in patients with impaired glucose tolerance (IGT). A randomized, double-blind, placebo-controlled clinical trial was performed in 30 patients with IGT; 15 patients randomly assigned to oral chlorogenic acid received 400 mg three times per day for 12 weeks, and the other 15 patients received placebo in the same way. Before and after the intervention, anthropometric and metabolic measurements, including fasting plasma glucose (FPG), glycated hemoglobin A1c, and a lipid profile, were performed. Area under the curve of glucose and insulin as well as the insulinogenic, Stumvoll, and Matsuda indices were calculated. Wilcoxon, Mann–Whitney U, and chi-square tests were performed, and P ≤ .05 was considered statistically significant. There were significant decreases in FPG (5.7 ± 0.4 vs. 5.5 ± 0.4 mmol/L, P = .002), insulinogenic index (0.71 ± 0.25 vs. 0.63 ± 0.25, P = .028), body weight, body mass index, waist circumference, triglycerides, total cholesterol, low-density lipoprotein cholesterol, and very low-density lipoprotein levels in the chlorogenic acid group, with an increment in the Matsuda index (1.98 ± 0.88 vs. 2.30 ± 1.23, P = .002). There were no significant differences in the placebo group. In conclusion, chlorogenic acid administration in patients with IGT decreased FPG and insulin secretion, while increasing insulin sensitivity and improving both anthropometric evaluations and the lipid profile.

Introduction

One of the early manifestations of glucose disturbances is impaired glucose tolerance (IGT), which appears by a pancreatic failure in beta-cell compensation for an underlying state of insulin resistance, primarily in hepatic, muscular, and adipose tissues.^1,2 Scientific evidence shows that patients with IGT substantially increase the risk of progression to type 2 diabetes mellitus (T2DM) as well as its vascular complications.^3,4 Experts point out that an effective treatment for IGT could decrease the onset of T2DM.² To date, pharmacological treatments to prevent T2DM are still under study. One of the most recommended medications is metformin, however, new strategies are needed to improve insulin resistance and thus limit the insulin secretory demand on beta-cells to stop or postpone the conversion of prediabetes to T2DM.⁵

Chlorogenic acid is also known as 5-O-caffeoylquinic acid, an ester of caffeic acid with quinic acid that belongs to the hydroxycinnamic acid family.⁶ Chlorogenic acid is the main polyphenol of green coffee beans that seems to have hypoglycemic effects similar to metformin by improving insulin resistance and other oral agents such as glitazones by increasing glucose uptake, apparently without side effects.^7,8 However, these findings have not been studied in patients with IGT. Therefore, considering the probable healthy properties of chlorogenic acid to improve the glucose homeostasis, the aim of this study was to evaluate the effect of chlorogenic acid on glycemic control, insulin secretion, and insulin sensitivity in patients with IGT.

Materials and Methods

A randomized, double-blind, placebo-controlled clinical trial was performed in 30 patients of both genders who ranged in age from 30 to 60 years, with newly diagnosed IGT according to the American Diabetes Association⁹ (defined as a 2-h postload plasma glucose [2-h PG] concentration between 7.8 and 11.1 mmol/L). All subjects were sedentary, nonsmokers, with a body mass index (BMI) between 25 and 39.9 kg/m² and a stable body weight (BWt), considering up to 5% changes in BWt for at least 3 months before the study.

All subjects were not taking any drug or nutritional supplement for at least 3 months before enrollment in the study. Exclusion criteria were prior T2DM diagnosis, high blood pressure, renal, heart, thyroid or hepatic disease, and women who were pregnant or breastfeeding.

Enrolled subjects underwent two assessments at baseline and at the end of the study (12-weeks). Tests were performed at 8:00 am after a 10- to 12-h overnight fast. BWt was measured with a digital scale and standing height with the subject standing barefoot with the head aligned in the Frankfort horizontal plane (Model TBF-300 A; Tanita, Tokyo, Japan). BMI was calculated as BWt (kg) divided by the square of body height (m²). Waist circumference (WC) was measured using a flexible tape at the midline between the highest point of the iliac crest and the lowest rib in the midaxillary line.

All the anthropometric measurements were performed with the individuals wearing light clothing without shoes and after evacuation of the bladder. Blood pressure was evaluated after a 15-min resting period with the individual sitting using a digital sphygmomanometer. The mean of three systolic and diastolic blood pressure measurements was considered.

Blood samples were collected from an antecubital vein after insertion of a catheter to determine fasting plasma glucose (FPG), glycated hemoglobin A1c (A1C), triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and fasting insulin concentrations. Subsequently, subjects underwent a 2-h oral glucose tolerance test (2-h OGTT) by consuming 75-g of a dextrose load, and two blood samples were obtained at 30, 60, 90, and 120 min after glucose administration. The first blood sample was used to determine plasma glucose immediately, and the second blood sample was frozen at −20°C for insulin determinations within the next 30 days.

All subjects before clinical and laboratory evaluations were instructed to avoid strenuous physical activity. To ensure proper insulin secretion, patients received an isocaloric diet 3 days before the 2-h OGTT, containing a minimum of 250 g of carbohydrates/day. All females were tested during the first phase of their menstrual cycle (days 3–8).

Glucose, TG, TC, and HDL-C levels were measured by colorimetric methods using an automated analyzer (Erba XL-100^®) with an intra- and interassay coefficients of variation (CV) of <1% and 2%, respectively. The A1C percentage was measured using ion-exchange high-performance liquid chromatography (Bio-Rad Laboratories, Hercules, CA, USA) with an intra- and interassay CV of 0.4% and 1.6%, respectively. Insulin concentrations were measured using a chemiluminescent immunoassay technique (Cortez Diagnostics, Woodland Hills, CA, USA) with an intra- and interassay CV of 6.0% and 4.1%, respectively. The area under the curve (AUC) of glucose and insulin was obtained using the trapezoidal integration.¹⁰

The total insulin secretion was calculated with the insulinogenic index [ΔAUC insulin/(ΔAUC glucose)],¹¹ the first phase insulin secretion was calculated using the Stumvoll index [1283 + 1.829 × insulin 30′ (mmol/L) −138.7 × glucose 30′ + 3.772 × insulin 0′ (pmol/L)],¹² and the insulin sensitivity with the Matsuda index [10,000/square root of (glucose 0′ × insulin 0′) × (mean glucose × mean insulin during 2-h OGTT)].¹³ Low-density lipoprotein cholesterol (LDL-C) levels were calculated with the Friedewald equation: LDL-C (mmol/L) = TC (mmol/L) − HDL-C (mmol/L) − [TG (mmol/L)/2.2], and the very low-density lipoprotein (VLDL) with the proportion of TG (mmol/L)/2.2.

Pharmacological administration

After simple random allocation using a computer-generated random number list, two groups of 15 subjects, received either oral capsules of chlorogenic acid (ResVitále™, Green coffee bean pure extract) or homologated placebo, 400 mg three times per day before breakfast, meal, and dinner (for a total 1200 mg/day) for 12 weeks. Throughout the study, the principal researcher evaluated monthly treatment compliances by capsule count-backs (adherence of at least 80% was considered as good) as well as the presence of adverse events. All patients were asked to register the appearance of adverse effects in their daily treatment diary, and they were instructed to maintain their habitual physical activity level. In addition, patients received general nutritional recommendations during the study period.

Statistical analysis

Sample size was calculated using a formula for mean differences¹⁴ for each of the primary variables with a statistical confidence of 95% and a statistical power of 80%. According to the largest sample size calculated from 2-h PG with a standard deviation (SD) of 0.8 mmol/L¹⁵ and an expected difference between-groups of at least 1.0 mmol/L, a total of 15 subjects per group was obtained, including 20% of expected loss. Data were analyzed using SPSS software (ver. 21.0; SPSS, Inc., Chicago, IL, USA).

After assessing normality, continuous data were compared using nonparametric tests; Wilcoxon signed-rank test and Mann–Whitney U-test to evaluate intra- and intergroup differences, respectively, and chi-square test to assess the differences in nominal variables. Continuous variables are presented as means ± SD and categorical variables as frequencies and percentages. Values are presented according to the International System of Units (SI). Intention to treat analysis was performed. Dropout cases were not replaced, and P ≤ .05 was considered statistically significant.

Ethical considerations

The present study was performed in accordance to ethical principles for medical research involving humans described in the international guidelines for Good Clinical Practices and the Declaration of Helsinki. Informed consent was obtained from all participants before the intervention and after being accurately informed regarding the nature, purpose, risks, and benefits of the study by the principal investigator. The protocol was registered at ClinicalTrials.gov as NCT02621060.

Results

Fifteen females with a mean age of 43 ± 11 years integrated the chlorogenic acid group and 10 females and 5 males aged 45 ± 9 years comprised the placebo group. Four patients withdrew from the study within the first 4 weeks, three from the chlorogenic acid group, and one from the placebo group, for reasons unlinked to the study drug.

At baseline, both groups had similar characteristics (Table 1). After chlorogenic acid administration, significant reductions in FPG, insulinogenic index, BWt, BMI, WC, TG, TC, LDL-C, and VLDL were found with an increase in the Matsuda index. There was a statistical trend toward the reduction of 2-h PG (P = .084), AUC of insulin (P = .074), and the Stumvoll index (P = .084). There were no significant differences in the placebo group (Table 1).

Table 1.

Characteristics Before and After Intervention

	Placebo		Chlorogenic acid
	Baseline (n = 15)	12 weeks (n = 12)	Baseline (n = 15)	12 weeks (n = 14)
BWt (kg)	81.3 ± 8.0	81.3 ± 7.9	83.3 ± 9.8	80.8 ± 11.0^*
BMI (kg/m²)	32.1 ± 2.5	32.0 ± 2.6	32.6 ± 2.4	31.4 ± 2.7^*
WC (cm)	103 ± 7	102 ± 5	106 ± 10	104 ± 10^*
SBP (mmHg)	120 ± 6	118 ± 9	115 ± 11	113 ± 8
DBP (mmHg)	77 ± 6	78 ± 7	77 ± 11	74 ± 10
FPG (mmol/L)	5.7 ± 0.4	5.8 ± 0.3	5.7 ± 0.4	5.5 ± 0.4^**
2-h PG (mmol/L)	9.0 ± 0.5	9.0 ± 0.8	8.8 ± 0.6	8.5 ± 0.4
A1C (%)	5.6 ± 0.5	5.8 ± 0.3	5.5 ± 0.3	5.5 ± 0.4
TG (mmol/L)	1.6 ± 0.7	1.7 ± 0.7	1.6 ± 0.6	1.3 ± 0.5^**
TC (mmol/L)	4.9 ± 1.0	5.3 ± 0.9	4.5 ± 0.6	4.3 ± 0.5^**
HDL-C (mmol/L)	1.5 ± 0.4	1.5 ± 0.3	1.7 ± 0.4	1.8 ± 0.3
LDL-C (mmol/L)	2.6 ± 1.1	2.7 ± 0.8	2.3 ± 1.0	1.9 ± 0.5^*
VLDL (mmol/L)	0.77 ± 0.36	0.77 ± 0.32	0.72 ± 0.30	0.61 ± 0.22^**
AUCG (mmol/L/min)	1139 ± 154	1187 ± 130	1119 ± 147	1145 ± 199
AUCI (pmol/L/min)	72,298 ± 24,627	67,322 ± 31,531	76,993 ± 26,480	72,857 ± 29,414
Insulinogenic index	0.58 ± 0.21	0.55 ± 0.26	0.71 ± 0.25	0.63 ± 0.25^*
Stumvoll index	1248 ± 701	1281 ± 818	1331 ± 628	1133 ± 601
Matsuda index	2.17 ± 0.71	2.43 ± 0.88	1.98 ± 0.88	2.30 ± 1.23^**

P < .05, ^** P < .01 between baseline and 12-week measurement within the Chlorogenic acid group (Wilcoxon rank test).

A1C, glycated hemoglobin A1c; AUCG, area under the curve of glucose; AUCI, area under the curve of insulin; BMI, body mass index; BWt, body weight; DBP, diastolic blood pressure; FPG, fasting plasma glucose; 2-h PG, 2-h postload plasma glucose; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; SBP, systolic blood pressure; TC, total cholesterol; TG, triglycerides; VLDL, very low-density lipoprotein; WC, waist circumference.

Adverse events were similar in both groups and these consisted of diarrhea, abdominal distention, abdominal pain, polyuria, and headache. All adverse events were considered not serious and disappeared after the first week of the intervention.

Discussion

To our knowledge, this is the first study to assess the effects of chlorogenic acid on subjects with IGT, showing that its administration improved glucose homeostasis, as well as some anthropometric variables, and the lipid profile. These findings are important because it has been demonstrated that early strategies for individuals with a high risk of developing T2DM may prevent or delay its occurrence.¹⁶

Accumulating evidence in vivo, animal and human models have suggested that chlorogenic acid has antidiabetic properties by improving the regulation of glucose homeostasis.^8,17,18 Although its mechanism of action is still under investigation, some theories suggest that the stimulation of insulin secretion dependent of the glucagon-like peptide 1 (GLP-1)¹⁹ and the activation of the adenosine 5′-monophosphate-protein kinase (AMP-K) dependent with the increase of the glucose uptake in skeletal muscle²⁰ could play a key role. Moreover, the attenuation of adipogenesis and proinflammatory cytokines with an increment in the translocation of glucose transporter type 4 (GLUT-4) in adipose and muscle tissue²¹ could also be important.

Related to glucose metabolism, after the administration of chlorogenic acid (80 mg/kg/day) by probe for 12 weeks to db/db mice, a significant reduction in FPG and A1C percentage was found.¹⁷ A clinical trial in 15 overweight men who received a single dose of 1 g of chlorogenic acid 30 min before a 75-g oral dextrose load showed that its administration decreased early fasting glucose and improved insulin response in comparison to the placebo group.¹⁸ Chlorogenic acid could also improve postprandial blood glucose concentration by inhibition of key enzymes linked to absorption of carbohydrates such as α-amylase, α-glucosidase, and pancreatic amylase isoenzymes I and II.^22,23

In the present study, patients treated with chlorogenic acid showed a significant decrease in FPG concentration, with a trend toward reduction in 2-h PG and without change in the A1C percentage. The above-mentioned finding was probably due to the dose of chlorogenic acid used, the treatment duration, the moderately elevated A1C levels in all patients, or the compensatory dynamic responses between insulin sensitivity and insulin secretion. As insulin sensitivity increases, the response of insulin secretion in the pancreas is reduced, which may have influenced a lower 2-h PG reduction.

The patients in this study increased their insulin sensitivity with a reduction of total insulin secretion, a statistical tendency to reduce the AUC of insulin, and the first phase of insulin secretion. These findings could be explained in addition to the above-mentioned mechanisms by the action of chlorogenic acid on hepatic proliferation-activated receptor-α (PPAR-α), which plays a role as a facilitator in clearing lipids from the liver and enhancing insulin sensitivity.²⁴ This effect could be related to the fat distribution after administration of chlorogenic acid with a decrease of BWt, WC, and BMI. However, further clinical trials must be considered to evaluate the hypoglycemic effect of chlorogenic acid on diabetic patients.

The effect of chlorogenic acid on BWt is promising but not yet conclusive, despite our positive results. In animals, chlorogenic acid has shown to prevent ectopic fat accumulation, specifically in the heart and liver of mice fed with a high-fat diet, including a BWt reduction close to 16%.²⁵ Various preclinical studies have revealed a putative mechanism of chlorogenic acid on visceral adipose tissue through the downregulation of genes associated with adipogenesis and inflammation.²⁶

Chlorogenic acid has also shown its potential as a therapeutic agent for dyslipidemia. In vitro experiments showed its possible role as a modulator in the secretion of adipokines of the adipokines secretion, upregulating the expression of PPAR-α.²⁴ Moreover, chlorogenic acid seems to play a critical role in fatty acid and TG homeostasis through the stimulation of hepatic enzymes such as fatty acid synthase, 3-hydroxy-3-methylglutaryl coenzyme A reductase, and acyl-coenzyme A cholesterol acyltransferase.²⁵ In the model of insulin resistant, obese, and hyperlipidemic (fa/fa) Zucker rats, the administration of intravenous chlorogenic acid (5 mg/kg/day) for 3 weeks, reduced TC and TG.²⁴

In addition, chlorogenic acid has claimed to reduce the risk of cardiovascular disease by decreasing lipid oxidation in humans and animals due to its free radical scavenging properties.^27,28 In the present research, chlorogenic acid improved the lipid profile. However, further studies in humans to confirm its benefits as a hypolipidemic agent are needed.

Some limitations of this study are recognized as follows: (1) the relative small sample size, although it was calculated with the variable that resulted with the largest number; (2) the distribution of sex, since the chlorogenic acid group included only women, so the results could not be generalized to both genders; (3) the dose of chlorogenic acid used was lower than the higher dose prescribed for humans, and (4) the secretion and insulin sensitivity were not estimated with the gold standard, even though the formulas used have a good correlation with the glucose-insulin clamp technique.

In conclusion, chlorogenic acid administration in subjects with IGT decreased FPG and insulin secretion, while increasing insulin sensitivity, showing its potential as an antiobesity and hypolipidemic agent.

Footnotes

Acknowledgment

The authors thank L. Michele Brennan-Bourdon, PhD, executive editor, Brennan Language Editing Services, for the English editorial assistance.

Author Disclosure Statement

No competing financial interests exist.

References

Kanata

, Defronzo

, Abdul-Ghani

: Treatment of prediabetes. World J Diabetes, 2015; 25:1207–1222.

Abdul-Ghani

, Tripathy

, DeFronzo

: Contributions of beta-cell dysfunction and insulin resistance to the pathogenesis of impaired glucose tolerance and impaired fasting glucose. Diabetes Care, 2006; 29:1130–1139.

Abdul-Ghani

, DeFronzo

, Jayyousi

, et al.: Prediabetes and risk of diabetes and associated complications: Impaired fasting glucose versus impaired glucose tolerance: Does it matter?. Curr Opin Nutr Metab Care, 2016; 19:394–399.

Saaristo

, Moilanen

, Korpi-Hyövälti , et al.: Lifestyle intervention for prevention of type 2 diabetes in primary healt care: One-year follow-up of the Finnish National Diabetes Prevention Program (FIN-D2D). Diabetes Care, 2010; 33:2146–2151.

Hostalek

, Gwilt

, Hildemann

: Therapeutic use of metformin in prediabetes and diabetes prevention. Drugs, 2015; 75:1071–1094.

Tajik

, Tajik

, Mack

, et al.: The potential effects of chlorogenic acid, the main phenolic components in coffee, on health: A comprehensive review of the literature. Eur J Nutr, 2017. [Epub ahead of print]; DOI:10.1007/s00394-017-1379-1.

Alonso-Castro

, Miranda-Torres

, Gonzalez-Chavez

, et al.: Cecropia obtusifolia Bertol and its active compound, chlorogenic acid, stimulate 2-NBDglucose uptake in both insulin-sensitive and insulin-resistant 3T3 adipocytes. J Ethnopharmacol, 2008; 120:458–464.

McCarty

: A chlorogenic acid-induced increase in GLP-1 production may mediate the impact of heavy coffee consumption on diabetes risk. Med Hypotheses, 2005; 64:848–853.

American Diabetes Association: Classification and diagnosis of diabetes. In Standards of Medical Care in Diabetes-2017. Diabetes Care, 2017; 40(Suppl 1):S11–S13.

10.

Tai

: A mathematical model for the determination of total area under glucose tolerance and other metabolic curves. Diabetes Care, 1994; 17:152–154.

11.

Dalfrà

, Pacini

, Parretti

, et al.: Elevated insulin sensitivity and beta-cell function during pregnancy in mothers of growth-restricted newborns. Am J Physiol Endocrinol Metab, 2011; 301:E25–E30.

12.

Stumvoll

, Mitrakou

, Pimenta

, et al.: Use of the oral glucose tolerance test to assess insulin release and insulin sensitivity. Diabetes Care, 2000; 23:295–301.

13.

Abdul-Ghani

, Matsuda

, Balas

, et al.: Muscle and liver insulin resistance indexes derived from the oral glucose tolerance test. Diabetes Care, 2007; 30:89–94.

14.

Jeyaseelan

, Rao

: Methods of determining samples size in clinical trials. Indian Pediatr, 1989; 26:115–121.

15.

Fernández

, Izquierdo

, Marset

, et al.: Evidence-based nutritional recommendations for the prevention and treatment of overweight and obesity in adults (FESNAD-SEEDO consensus document). The role of diet in obesity prevention (II/III). Nutr Hosp, 2012; 27:800–832.

16.

Gillies

, Abrams

, Lambert

, et al.: Pharmacological and lifestyle interventions to prevent or delay type 2 diabetes in people with impaired glucose tolerance: Systematic review and meta-analysis. BMJ, 2007; 334:1–9.

17.

Jin

, Chang

, Zhang

, et al.: Chlorogenic acid improves late diabetes through adiponectin receptor signaling pathways in db/db mice. PLoS One, 2015; 10:e0120842.

18.

van Dijk

, Olthof

, Meeuse

, et al.: Acute effects of decaffeinated coffee and the major coffee components chlorogenic acid and trigonelline on glucose tolerance. Diabetes Care, 2009; 32:1023–1025.

19.

Tunnicliffe

, Eller

, Reimer

, et al.: Chlorogenic acid differentially affects postprandial glucose and glucose-dependent insulinotropic polypeptide response in rats. Appl Physiol Nutr Metab, 2011; 36:650–659.

20.

Ong

, Hsu

, Tan

: Chlorogenic acid stimulates glucose transport in skeletal muscle via AMPK activation: A contributor to the beneficial effects of coffee on diabetes. PLoS One, 2012; 7:e32718.

21.

, Gao

, Liu

: Chlorogenic acid improves high fat diet-induced hepatic steatosis and insulin resistance in mice. Pharm Res, 2015; 32:1200–1209.

22.

Oboh

, Agunloye

, Adefegha

, et al.: Caffeic and chlorogenic acids inhibit key enzymes linked to type 2 diabetes (in vitro): A comparative study. J Basic Clin Physiol and Pharmacol, 2015; 26:165–170.

23.

Narita

, Inouye

: Kinetic analysis and mechanism on the inhibition of chlorogenic acid and its components against porcine pancreas alpha-amylase isozymes I and II. J Agric Food Chem, 2009; 57:9218–9225.

24.

Rodriguez de Sotillo

, Hadley

: Chlorogenic acid modifies plasma and liver concentrations of: Cholesterol, triacylglycerol, and minerals in (fa/fa) Zucker rats. J Nutr Biochem, 2002; 13:717–726.

25.

Cho

, Jeon

, Kim

, et al.: Chlorogenic acid exhibits anti-obesity property and improves lipid metabolism in high-fat diet-induced-obese mice. Food Chem Toxicol, 2010; 48:937–943.

26.

Song

, Choi

, Park

: Decaffeinated green coffee bean extract attenuates diet-induced obesity and insulin resistance in mice. Evid Based Complement Altern Med, 2014; 2014:718379.

27.

Lecoultre

, Carrel

, Egli

, et al.: Coffee consumption attenuates short-term fructose-induced liver insulin resistance in healthy men. Am J Clin Nutr, 2014; 99:268–275.

28.

Nardini

, D'Aquino

, Tomassi

, et al.: Inhibition of human low-density lipoprotein oxidation by caffeic acid and other hydroxycinnamic acid derivatives. Free Radic Biol Med, 1995; 19:541–552.